This is a lot like hiring for great iOS / android developers. And also great web developers, FWIW. IME, the most value-generative and knowledgeable frontend/UI

This is a lot like hiring for great iOS / android developers. And also great web developers, FWIW. IME, the most value-generative and knowledgeable frontend/UI people I've worked with have all had really "weird" backgrounds and would fail a "standard" software engineering interview loop, and most would fail hard. I've worked at a bunch of companies that tried to have the same hiring process for frontend and backend engineers, and it's never made sense to me.